The present invention relates to a radial tire for motor cycles which can alleviate the ply separation at both edges of belt layer without reducing the rigidity of shoulder region of a tire tread.
In recent years, in company with arrangement of the highway networks and high speed use of vehicles, radial tires have been introduced to the motor cycle. On the other hand, such a tire for motor cycles has a tread region in which the radius is rather small in comparison with that of a tire for a passenger car, and therefore, the shearing strain produced by the tread deformation under load becomes larger, and rubber separation at both belt edges is apt to occur.
Accordingly, to prevent the rubber separation, heretofore, as shown in FIG. 2, the belt layer A is composed of a plurality of belt plies, generally three cut end belt plies B1, B2 and B3, wherein the belt widths are different relative to each other. The belt plies are superimposed one upon another with the wider width being on the carcass side so as to alleviate the rigidity difference at both edges of said belt layer A.
However, such belt layer A constructed as above become unsatisfactory in the rigidity at the tread shoulder S, so that the steering stability, such as running stability during cornering, is remarkably deteriorated.